Fatores geográficos e climáticos determinantes da ocorrência de paracoccidioides spp. no Estado do Espírito Santo, Brasil

Abstract

Paracoccidioidomycosis (PCM) is a fungal infection caused by Paracoccidioides spp, which originally occurs in Latin America, and even 114 years after the identification of the agent, its ecological niche is still poorly understood. This study aims to define the geographic and climatic variables that determine the occurrence of natural niches of the fungus, which favor the occurrence of human infection by Paracoccidioides in the state of Espírito Santo, an important region with endemism in Southeast Brazil. The study population consisted of cases diagnosed with PCM and treated at the Infectious Diseases Unit of the University Hospital Cassiano Antônio Moraes from the Federal University of ES, Brazil from 1978 to 2018. Epidemiological data were collected through the information contained in medical records and, the environmental data, from georeferencing locations of origin of the patients. Climatic data were obtained from the WorldClim database and geographic information was retrieved from the National Institute for Space Research (INPE) and the Integrated System of Geospatial Bases of the state of Espírito Santo (GEOBASES). For the construction of the distribution models of Paraccoccidioides, the maximum entropy algorithm (MIAmaxent R package) was used, capable of estimating the probable distribution of a certain species in the studied area, from presence-only data. The validation of the ecological niche models was performed using the Receptor Operation Characteristic Curve (ROC-plot). The variables that contributed the most to the construction of the predictive model of the ecological niche of Paracoccidioides were precipitation in the wettest month (BIO 13), with 53% of the contribution, precipitation in the driest season (BIO 17), with 25%, solar radiation – 12-month minimum value (SRADI), with 11%, water vapor pressure – 12 month standard deviation (VAPRD), with 11% and soil type (GEOBASES), with a contribution of 6%. In addition to quantifying the contribution of each variable and highlighting the importance of precipitation in the construction of the model, this study demonstrates for the first time the contribution of solar radiation and water vapor pressure in the occurrence of the fungus. These results can also guide public investments in training health teams regionally, for early diagnosis and treatment of PCM, this potentially disabling and deadly disease. In addition to identifying areas with a higher probability of occurrence of natural niches of Paracoccidioides here in the state, our findings can also be extrapolated to neighboring states in Southeast Brazil, where areas with climate and topography like those of Espírito Santo appear